After powering up his PC, Bob notices the PC was not able to properly connect to network devices. He obtained the following information from his workstation:

C:\>ipconfig

Windows IP Configuration

Ethernet adapter El90x1:

Connection-specific DNS Suffix....:

IP Address. . . . . . . . ..................: 169.254.55.187

Subnet Mask . . . . . . ................. : 255.255.0.0

Default Gateway . . . ................. :

He called the IT department for help (he was on hold for 5 minutes). When the IT tech support person got on the phone, Bob's PC had already begun working properly. Bob then obtained the following information from his workstation.

C:\>ipconfig

Connection-specific DNS Suffix....:

IP Address. . . . . . . . ..................: 139.100.110.50

Subnet Mask . . . . . . ................. : 255.255.0.0

Default Gateway . . . ................. : 139.100.110.1

a. Explain in detail what occurred.

b. How can Bob account for the first IP stack entries?

c. How would you explain the changes to the IP stack?